Those least able to keep up with their credit-card payments are accounting for a greater share of consumer debt, according to a study by Peter S. Yoo of the Federal Reserve Bank of St. Louis.

In 1995, households with below-median income held 30 percent of all credit-card debt in the U.S. -- up from 22 percent in 1983.

Their average credit-card debt rose 14 percent a year from 1992 to 1995.

That compares with 8 percent annual debt growth among households in the upper half of the income scale.

The number of households with credit cards grew 2.4 percent a year from 1992 to 1995 -- while the average balance grew at a more rapid rate of 9.6 percent.

So most of the rise in outstanding credit-card debt comes from increases in average balances, rather than in the number of people holding credit cards. Yoo interprets that as good news -- since people who already use credit cards presumably know how to handle them better than people signing up for the first time.

Source: Peter Coy, "The Poor Get Deeper in Debt," Business Week, June 1, 1998.